1. Field of the Invention
The present invention relates generally to semiconductor manufacturing and, specifically, to a pressurized diffuser in wet processing systems.
2. Background
Semiconductors are used in highly sophisticated equipment, such as computers and the like. Semiconductor chips or dies are typically batch fabricated on a silicon wafer. The wafer may contain hundreds of chips arranged in a matrix. The chips are separated by sawing the semiconductor wafer into small squares or rectangles. Each chip is then mounted on an appropriate substrate, contacted and packaged.
During the fabrication of semiconductor wafers, several process steps involve contacting the wafers with fluids. These include, for example, etching and rinsing of the wafers. The wafer surface is treated with the appropriate liquid(s) to create the desired etch pattern or to cleanse the wafer surface from contaminants. This wet processing generally utilizes a tank or bath in which one or more wafers are present. Typically, liquid flows over the wafer(s) and is either recirculated or drained.
It can be difficult to provide a uniform flow of liquid in wet processing systems. Uneven fluid flow can lead to unreliable results. For example, the etch pattern formed on the wafers may be unpredictable. Also, the wafers may not be thoroughly cleaned, and hence residual contaminants may remain on the wafer surface. The undesirable effects of this uneven fluid flow can be particularly severe as the end product devices become more miniaturized and complex.
The invention relates to a diffuser for wet processing systems involved in the manufacturing of semiconductor wafers. The diffuser includes a plenum section and a slitted section. Pressurized fluid from the plenum section is forced through the slitted section and across a plurality of wafers mounted in the wet processing system. One advantage is that by xe2x80x9cdiffusingxe2x80x9d pressurized fluid through the slitted section a generally uniform and/or laminar flow is achieved. Desirably, the diffuser provides a more reliable, and hence more cost-effective, technology for wet processing fabrication of semiconductor wafers.
One embodiment of the invention relates to a wet semiconductor processing system. The wet semiconductor processing system comprises a plurality of wafers housed therein. The wet semiconductor processing system further comprises a diffuser in liquid communication with the wafers. The diffuser comprises a plurality of plenums adapted to receive a supply of fluid. The diffuser further comprises a plate in fluid communication with the plurality of plenums. The plate comprises a plurality of slits, whereby the slits provide a generally uniform flow across the wafers.
Another embodiment relates to a sparger for a wet processing system. The sparger comprises a surface with a plurality of slits formed therein, whereby fluid flow emanating through the surface is generally uniform. Yet another embodiment relates to a wet processing system. The wet processing system comprises a tank that houses a plurality of wafers. The wet processing system further comprises a diffuser positioned generally below the wafers. The diffuser comprises a slitted surface.
A further embodiment relates to a semiconductor processing apparatus which comprises a tank. The tank holds one or more wafers. The semiconductor processing apparatus further comprises a distributor positioned generally above the wafers wherein the distributor comprises a slotted plate.
One aspect of the invention relates to a method for diffusing fluid through a wafer processing system. The method comprises the acts of pressurizing fluid and forcing the fluid through a plurality of slits. The fluid emanating through the plurality of slits has a generally uniform flow pattern.
Another aspect of the invention relates to a method of manufacturing a diffuser for a semiconductor processing system. The method comprises the acts of forming a plurality of plenums in a first plate and forming a plurality of slits in a second plate. The method further comprises the act of attaching the first plate and the second plate so that the first plate and the second plate are in fluid communication.
Yet another aspect of the invention relates to a method for wet processing of wafers. The method comprises the acts of supporting one or more wafers in a tank and diffusing pressurized fluid through a plurality of slits, whereby a generally laminar flow is provided across the one or more wafers.
Another embodiment relates to a sparger. The sparger comprises a first section with a plurality of plenums adapted to receive a supply of fluid. The sparger further comprises a second section in communication with the first section. The second section includes a generally staggered slit pattern to pressurize the fluid within the first section. The slit pattern includes a plurality of rows of slits arranged in a repetitive alternating pattern with each row including one or more of the slits.
An additional embodiment of the invention relates to a pressurized liquid diffuser for a wet processing system. The diffuser comprises a plenum plate including five plenums for receiving a supply of liquid. The plenums are generally rectangular in shape and fabricated from polyvinylidene fluoride (PVDF). The diffuser further comprises a slitted plate in mechanical and fluid communication with the plenum plate. The slitted plate is configured to pressurize the liquid within the plenum plate. The slitted plate is generally rectangular in shape and includes fifty rows of slits. Each row includes at least three of the slits arranged and configured to form an alternating slit pattern between at least two of the rows.
For purposes of summarizing the invention, certain aspects, advantages and novel features of the invention have been described herein above. Of course, it is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.